1. Field of the Invention
This invention pertains generally to sensors for switchgear and, more particularly, to such sensors for a power bus.
2. Background Information
Electrical sensors of various types are used to detect the current flowing through a conductor. Such sensors include, for example, a single Hall effect sensor that produces an output voltage indicative of the current magnitude as well as more conventional current sensors such as a shunt resistor.
Hall effect devices have been used to sense variations in magnetic flux resulting from a flow of current through a conductor. Some of these known devices have used a flux concentrator to concentrate magnetic flux emanating from the flow of current through the conductor. It has previously been suggested that electrical current sensing apparatus could be constructed in the manner disclosed in U.S. Pat. Nos. 4,587,509; and 4,616,207.
It is also known to measure the current in a conductor with one or two appropriately placed Hall sensors that measure flux density near the conductor and to convert the same to a signal proportional to current. See, for example, U.S. Pat. Nos. 6,130,599; 6,271,656; 6,642,704; and 6,731,105.
Non-conventional current sensors that employ a pair of magnetic field detectors have special requirements. One of these requirements is that the magnetic field detectors are parallel to one another. Another requirement may be that the corresponding electronic circuit card is disposed as closely as possible to the magnetic field detectors for purposes such as packaging, convenience and noise suppression. Furthermore, it may be advantageous to provide a current sensor assembly that can be mounted to conductors having various sizes and shapes.
U.S. Pat. No. 6,642,704 discloses a current sensor assembly that maintains a pair of magnetic field detectors parallel to one another and closely disposed to an electronic circuit card. Furthermore, the magnetic field detectors are selectively adjustable in order to be attached to a variety of electrical power conductors.
There exists the need for switchgear devices to safely provide electrical isolation and reliably determine, for example, the temperature and/or the current of the power busses thereof.
Accordingly, there is room for improvement in sensors for switchgear or power busses.